Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

8 hosts · 247 ms

HostCertsFirst seenLast seen
lonsys.co.uk 5 2026-05-29 2026-09-01
track.lonsys.co.uk 5 2026-05-17 2026-09-13
horizon.lonsys.co.uk 1 2026-01-15 2026-01-15
help.lonsys.co.uk 3 2026-02-22 2026-10-06
cwwebapp.lonsys.co.uk 4 2026-02-22 2026-10-06
future-tickets.lonsys.co.uk 2 2026-02-24 2026-06-16
mta-sts.lonsys.co.uk 5 2026-05-15 2026-09-12
www.lonsys.co.uk 5 2026-05-29 2026-09-01

Programmatic access: API GET /v1/hosts/lonsys.co.uk (API key for paging).

Shown here: hostnames with a certificate that is valid now or expired within the last 90 days. The full history since 2013 — hostnames whose last certificate expired earlier — is a Pro plan method: GET /v1/hosts-history/lonsys.co.uk.